The present invention relates to apparatuses and methods for allocating communications-related services provided by a base station site to mobile units in communication with an antenna of the base station site.
Communications systems often employ a base station site which communicates via RF links with a plurality of mobile units. The base station site typically contains an antenna and an antenna controller. For example, in a cellular telephone system, the base station site for a given cell includes an antenna and controller, which can communicate with a plurality of cellular telephones (mobile units) within the cell. Each mobile unit, as well as the base station site, thus has a transceiver. Each mobile unit is typically utilized by a subscriber or customer of a communications system of which the base station is part.
Various communications schemes may be employed to permit RF communications between the base station and the mobile units, such as time division multiple access (TDMA), frequency division multiple access (FDMA), code division multiple access (CDMA), and combinations of such schemes. Both digital and analog communications are possible. Various modulation schemes are employed, such as carrierless amplitude/phase (CAP) and quadrature amplitude modulation (QAM).
The base station thus provides communication services, such as supporting communications on inbound and outbound links, to each mobile unit. The terms inbound and outbound are used herein from the perspective of the antenna. Thus, inbound refers to transmissions from a mobile unit to a base station antenna, and outbound refers to transmissions from the base station antenna to the mobile units.
Smart antennas are often used to improve the signal-to-noise ratio of the inbound and outbound links. Referring now to FIG. 1, there is shown a prior art communications system, employing a smart, directional antenna 101 and a plurality of mobile units 110. In such a system, directional antenna 101 typically attempts to optimize the outbound and inbound signal for a given mobile unit 111. This may be done, for example, by extending a lobe in the direction of the mobile unit to obtain a better signal-to-noise ratio, as illustrated. This improves the communications links provided to the mobile unit by the antenna and base station, and thus provides a longer range or a higher data rate for that mobile unit.
Advanced smart antennas can generate multi-lobe patterns that can provide improved or enhanced service to more than one mobile unit at a time. For example, a given smart antenna may be able to selectively extend two or more lobes at a given time. The number of lobes that can be extended is typically limited, however, by physical, design, economic, or other constraints.
Because the services available, such as lobe extensions and the resulting improved communications links, are limited, the base station controller unit must somehow allocate these limited services (scarce resources) to existing mobile units. In one scheme, the controller attempts to treat all mobile units equally. However, this results in more or less uniform, and potentially poor, service. This may be referred to as a socialist or egalitarian solution. Alternatively, the base station can attempt to allocate resources so as to optimize some global system performance characteristics. Such approaches, however, do not effectively allocate scarce resources to the most urgent subscribers. There is a need, therefore, for improved techniques for allocating scarce base station communications-related resources to mobile units in need of these resources.